The long-range mineral scanner can detect mineral deposits in the nearby areas outside your colony when manned by a researcher. It can be tuned to different minerals, such that it will only find deposits of a certain kind.

The scanner spawns mineral lumps mini-maps in the world map and triggers its respective world event which always has an expiry date of 30 days. They can either be unguarded, guarded by pirates or surrounded by a manhunter pack. Once the area is clear of hostiles, you have 10 days to mine everything before the caravan leaves.

Pirate defenders will surround the lump with a rudimentary base and possibly turrets.

Manhunter packs will charge at your colonists. Some are slow allowing evasion and kiting, while others are fast and require a defensive stance.

The amount of time taken is random, though better researchers increase the chances that a mineral deposit may be found.

Resources

All minerals, as well as components, can be discovered with the scanner.

Steel is found in medium-sized lumps of approximately 50 tiles; you can get at least 1000 steel from a single lump.

Plasteel is found in small lumps of around 10 - 15 tiles, netting 300 - 500 plasteel.

Components are found in large lumps, that can amount to more than 100 components once mining is finished.

Silver is found in massive lumps, and one can easily get upwards of 3000 silver from a single lump.